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PlasmaPy: an open source community-developed Python package for plasma physics
No abstract provided.
Different Detector Types Used in Plasma Physics Experiment
We analyzed the possibility of using different detector types (semiconductor, scintillator, thermoluminescent, nuclear emulsions) for plasma diagnostics. We investigated the main characteristics of such detectors, on the basis of which an X-ray spectrometer complex was created.
Collaborative Research: Experimental and Theoretical Study of the Plasma Physics of Antihydrogen Generation and Trapping (Final Technical Report)
The charge-parity-time (CPT) invariance principle and the weak equivalence principle (WEP) undergird our current understanding of Nature. CPT, which is based on only Lorentz invariance, locality, and spin-statistics, is basic to local relativistic quantum field theory (QFT) models of physical laws. Testing established principles like these is a long-standing and honorable tradition in physics. Beginning with Newton’s Laws, many firmly established laws have been superseded, often to the great surprise of contemporaneous physicists. Certainly, CPT rests on firmer grounds than the earlier widely believed, but erroneous principles, of parity (P) and charge-parity (CP) invariance, but this does not necessarily make CPT inviolable. Tests of CPT confront the entire framework of QFT, and are quite distinct from most other “beyond the Standard Model” searches, which look for new physics within the QFT framework. With the failure, so far, to find new physics at the LHC or in dark matter searches, the motivation to test QFT itself is urgent. The revolutionary consequences of CPT and WEP violation would be so great that these principles are under intense scrutiny in many different systems. Here we focus on tests of CPT and WEP that employ antimatter, specifically antihydrogen. Such tests are difficult to realize experimentally, but constitute some of the simplest and most profound matter-antimatter comparisons that can be performed. Antimatter particles have been investigated since the prediction and subsequent discovery of the positron in the 1930s. That early discovery motivated the search for the antiproton, culminating in its creation and detection in Berkeley two decades later. As far as we know today, particles and their antiparticles share identical properties except for the sign of their charge. Antihydrogen is the simplest antimatter system—it is the antiparticle of the simplest atom, hydrogen. Differences between the spectra of the two are forbidden by CPT. The weak equivalence principle (WEP), demands that matter and antimatter accelerate identically in a gravitational field. WEP has never been subjected to a direct, free fall test using antimatter. Because of the weakness of the gravita tional force, direct antimatter WEP tests must employ a neutral particle, of which antihydrogen is the simplest to obtain. There are reasons to suspect that something is amiss with our understanding of antimatter. All generally accepted theories of the Big Bang predict that roughly equal amounts of matter and antimatter should have been created. Instead, very little antimatter has been observed in the Universe. This baryogenesis problem is arguably the most fundamental issue with the theory of the Big Bang. Its resolution may come from the discovery of enhanced CP violation, but could also come from CPT or WEP violation.
The expansion of a plasma into a vacuum - Basic phenomena and processes and applications to space plasma physics
In this review attention is called to basic phenomena and physical processes involved in the expansion of a plasma into a vacuum, or the expansion of a plasma into a more tenuous plasma, in particular the fact that upon the expansion, ions are accelerated and reach energies well above their thermal energy. Also, in the process of the expansion a rarefaction wave propagates into the ambient plasma, an ion front moves into the expansion volume, and discontinuities in plasma parameters occur. The physical processes which cause the above phenomena are discussed, and their possible application is suggested for the case of the distribution of ions and electrons (hence plasma potential and electric fields) in the wake region behind artificial and natural obstacles moving supersonically in a rarefied space plasma. To illustrate this, some in situ results are reexamined. Directions for future work in this area via the utilization of the Space Shuttle and laboratory work are also mentioned.
Topics in Plasma Physics
During the period 1998-2013, research under the auspices of the Department of Energy was performed on RF waves in plasmas. This research was performed in close collaboration with Josef Preinhaelter, Jakub Urban, Vladimir Fuchs, Pavol Pavlo and Frantisek Zacek (Czech Academy of Sciences), Martin Valovic and Vladimir Shevchenko (Culham). This research is detailed and all 38 papers which were published by this team are cited.
Foreword to Special Issue: Papers from the 56th Annual Meeting of the APS Division of Plasma Physics, October 27–31, 2014, New Orleans, Louisiana, USA
No abstract prepared.
Example space plasma physics study with Hybrid-VPIC code on Chicoma [Slide]
Abstract not provided.
Unitary Qubit Lattice Algorithms for Plasma Physics
This final technical report summarizes research conducted under DOE Award DE-SC0021653 to develop unitary Quantum Lattice Algorithms for modeling electromagnetic wave propagation and scattering in complex media, including plasmas. The project developed and validated quantum-inspired formulations of Maxwell's equations that preserve unitary evolution and can be evaluated on classical high-performance computing systems while providing a foundation for future quantum-computing implementations. Major accomplishments include the development of two- and three-dimensional algorithms for electromagnetic scattering; scalable, distributed-memory implementations demonstrated on the Perlmutter supercomputer; formulations for nonlinear lossless fluid dynamics and cold, lossless, inhomogeneous magnetized plasmas; and an explicit quantum algorithm for a time-discretized Lorenz model. Simulations reproduced a range of characteristic wave phenomena, including transient effects that are not readily apparent in conventional frequency-domain studies, demonstrating the effectiveness of the proposed approach for modeling complex electromagnetic and plasma systems. The work establishes a unified theoretical and computational framework for quantum and quantum-inspired simulation and provides a foundation for future implementation on fault-tolerant quantum systems.
Space plasma physics: I - Stationary processes
The physics of stationary processes in space plasmas is examined theoretically in an introduction intended for graduate students. The approach involves the extensive use of numerical simulations. Chapters are devoted to fundamental principles, small-amplitude waves, and the stationary solar plasma system; typical measurement data and simulation results are presented graphically.
Viscosity in a magnetized plasma - Physical interpretation
The viscosity of a fully ionized H plasma in a magnetic field is investigated theoretically, revising the derivation proposed by Braginskii (1965) for the viscous-stress-tensor viscosity coefficient eta(0). It is shown that eta(0) terms can be attributed to the tendency of the plasma to produce small thermal anisotropies during its evolution, and hence that they are fully incorporated in the gyrotropic diagonal pressure tensor, neglecting the off-diagonal terms. The role of collisions in preventing anisotropy production (and thus causing irreversible heating) is explored, and the implications of the eta(0) terms for the physics of 1000-10,000-km-scale structures in the solar corona are indicated.
Correction to the paper “a simple model to determine the interrelation between the integral characteristics of hall thrusters” [Plasma Physics Reports 40, 229 (2014)]
The paper is devoted to comparison of experimental data with theoretical predictions concerning the dependence of the current of accelerated ions on the operating voltage of a Hall thruster with an anode layer. The error made in the paper published by the authors in Plasma Phys. Rep. 40, 229 (2014) occurred because of a misprint in the Encyclopedia of Low-Temperature Plasma. In the present paper, this error is corrected. It is shown that the simple model proposed in the above-mentioned paper is in qualitative and quantitative agreement with experimental results.
Development of Multistep and Degenerate Variational Integrators for Applications in Plasma Physics
Geometric integrators yield high-fidelity numerical results by retaining conservation laws in the time advance. A particularly powerful class of geometric integrators is symplectic integrators, which are widely used in orbital mechanics and accelerator physics. An important application presently lacking symplectic integrators is the guiding center motion of magnetized particles represented by non-canonical coordinates. Because guiding center trajectories are foundational to many simulations of magnetically confined plasmas, geometric guiding center algorithms have high potential for impact. The motivation is compounded by the need to simulate long-pulse fusion devices, including ITER, and opportunities in high performance computing, including the use of petascale resources and beyond. This dissertation uses a systematic procedure for constructing geometric integrators - known as variational integration - to deliver new algorithms for guiding center trajectories and other plasma-relevant dynamical systems. These variational integrators are non-trivial because the Lagrangians of interest are degenerate - the Euler-Lagrange equations are first-order differential equations and the Legendre transform is not invertible. The first contribution of this dissertation is that variational integrators for degenerate Lagrangian systems are typically multistep methods. Multistep methods admit parasitic mode instabilities that can ruin the numerical results. These instabilities motivate the second major contribution: degenerate variational integrators. By replicating the degeneracy of the continuous system, degenerate variational integrators avoid parasitic mode instabilities. The new methods are therefore robust geometric integrators for degenerate Lagrangian systems. These developments in variational integration theory culminate in one-step degenerate variational integrators for non-canonical magnetic field line flow and guiding center dynamics. The guiding center integrator assumes coordinates such that one component of the magnetic field is zero; it is shown how to construct such coordinates for nested magnetic surface configurations. Additionally, collisional drag effects are incorporated in the variational guiding center algorithm for the first time, allowing simulation of energetic particle thermalization. Advantages relative to existing canonical-symplectic and non-geometric algorithms are numerically demonstrated. All algorithms have been implemented as part of a modern, parallel, ODE-solving library, suitable for use in high-performance simulations.
Space plasma physics at the Applied Physics Laboratory over the past half-century
An overview is given of space-plasma experiments conducted at the Applied Physics Laboratory (APL) at Johns Hopkins University including observational campaigns and the instrumentation developed. Specific space-plasma experiments discussed include the study of the radiation environment in the Van Allen radiation belt with solid-state proton detectors. Also described are the 5E-1 satellites which acquired particle and magnetic-field data from earth orbit. The Triad satellite and its magnetometer system were developed for high-resolution studies of the earth's magnetic field, and APL contributions to NASA's Interplanetary Monitoring Platforms are listed. The review mentions the International Ultraviolet Explorer, the Atmosphere Explorer mission, and the Active Magnetic Particle Tracer Explorers mission. Other recent programs reviewed include a high-latitude satellite, contributions to the Voyager mission, and radar studies of space plasmas.
Collaborative Research: Experimental and Theoretical Study of the Plasma Physics of Antihydrogen Generation and Trapping. Final Technical Report
The accomplishments at UNT that resulted from the DOE award are associated with the development of new knowledge reported in scientific publications. The new knowledge represents an improved understanding of various phenomena and scientific innovations, which include the following: artificially structured boundary for producing a spatially, periodic field; space-charge based plasma confinement; magnetic plasma expulsion; magnetobound positronium and protonium; quasibound antihydrogen; and, aperture-based antihydrogen gravity experiment. Other accomplishments at UNT that resulted from the DOE award are associated with research training provided to UNT students. All of the people who worked on the project at UNT were students, except for the UNT PI and one other UNT faculty member. The project has provided training opportunities for students who enrolled in courses such as Senior Thesis, Master’s Thesis, and Doctoral Dissertation. Such courses can apply towards a degree. The project has provided financial support for students who served as research assistants. The project has also provided opportunities for research to members of underrepresented groups. The work carried out by students as part of the research training they received was supervised by the PI to assure professional quality, and the team reported the research results in peer-reviewed journals and at technical conferences.
Plasma physics
Collision effects on cold and warm electron beams in plasma with spatial-temporal development
Errors in the use of mass analyzers in plasma physics.
Errors of charged-particle analyzer resulting from expansion of plasma beam within and without analyzer